The research revealed that Trump has been thinking and talking about nuclear weapons for a sustained period of time. In a 1984 interview, Trump revealed that he had a “fantasy” of becoming an arms control negotiator, something he has been publicly discussing ever since. The 2016 Presidential campaign focused more so on Trump’s personal character than on the substance of his views, which are now shaping national strategy and policy. His own biographical ghost-writer, Tony Schwartz, commented that if Trump became President and had access to the nuclear codes “there is an excellent possibility it will lead to the end of civilization.” So how worried should we be about Trump in charge of the US nuclear arsenal?

The biggest source of surprise in our study was how consistent Trump has been in his views on nuclear weapons. Since the 1990 Playboy interview, he has been concerned about the status of the nuclear arsenal and whether or not it is truly credible due to a lack of investment and infrastructure problems. He has consistently been interested in arms control to showcase his negotiating skills, whilst simultaneously remaining sceptical of deep reductions, disarmament, and any no-first-use declarations, as this would be “taking options off the table.”

In many ways, Trump’s views on nuclear weapons are nothing particularly new. Obama increased investment in the US nuclear infrastructure, which indeed is in need of attention. Additionally, Obama called for increased burden-sharing among NATO allies, though perhaps more delicately compared to Trump’s label of NATO members benefiting from a “free ride.” Furthermore, previous Republican presidents expressed scepticism about limiting America’s strategic options, including arms control.

Of course, Trump’s nuclear policies will also be shaped by those around him. For example, while Trump has consistently accused China of failing to “solve” the problem of North Korea’s nuclear development, Secretary of Defense James Mattis has stated that working with China would be preferable to any military actions. Mattis has also been a strong advocate of American leadership abroad and recently visited US allies in Asia and Europe, including a stop at the Munich Security Conference where he stated, “security is always best when provided by a team.”

But there is also cause for concern about Trump’s statements on nuclear weapons. In one very important way, Trump significantly differs from his predecessors, shuns the constraints of his advisors, and presents a nuclear risk: his use of Twitter. Many of Trump’s nuclear-related tweets raise important questions about social media as a disruptive technology. For example, recent scholarship has highlighted the importance of “audience costs” in strategic signalling, whereby if a leader fails to deliver on a threat, he/she will suffer a loss of credibility in the eyes of allies and adversaries. But what is the audience cost of a tweet? Tweets are often off-the-cuff remarks without the benefit of expert advice or fact-checking. Should tweets be interpreted as credible policy statements?

Additionally, nuclear signals are often misinterpreted, particularly in times of crisis when tensions are high and decision-making time is short. Are tweets more prone to misperception than other means of signalling? It is extremely difficult to communicate such signals in 140-characters or less- Trump has offered plenty of recent examples to help prove this point. Our study did not find any clear answers to these questions, but rather highlighted the need for further research and scholarship into these policy issues.

One example of this was on December 22, 2016, when Trump tweeted, “The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes.” This could be interpreted as reinforcing Trump’s pre-established views: he is not interested in nuclear disarmament and wants to increase investment in the US nuclear infrastructure. At the same time, it suggests an arms race, which Trump later confirmed in a discussion with Mika Brzezinski, a journalist and presenter on Morning Joe, and potentially undermines America’s commitment to organizations such as the Nuclear Non-Proliferation Treaty and agreements such as the 2010 New Strategic Arms Reduction Treaty with Russia.

After attempting to decipher Trump’s statements on nuclear weapons, our study raised three big questions. First, how committed is Trump to providing nuclear security guarantees to America’s allies? The early days of the Administration have suggested it will indeed be committed to allies as demonstrated in the actions and statements of General Mattis, in particular.

Second, is there a future for US-Russia arms control? Ultimately, this will remain unclear until Putin meets Trump. While there are limited prospects for further arms control, Trump has a thirty-year-old fantasy of being an arms control negotiator and he might not want to miss the opportunity. Instead, arms control may have to get creative.

Lastly, how does social media interact with traditional means of strategic signalling? This remains to be seen. But an additional cause for concern is that of an unpredictable nature: a strategic shock. This could be positive, such as the rise of Gorbachev which offered Reagan an opportunity to pursue arms control and reduce Cold War tensions. But strategic shock can also be negative, such as the terrorist attacks of September 11, which significantly shaped the Presidency of George W. Bush. Trump remains untested in his role as a crisis leader, but when the time comes, his instinct to take to Twitter may sow more confusion than security.